The physics of recoil

[kimel]

Hi Everyone,

I have been playing with various loads looking for a nice, soft shooting, yet major PF load.

In that quest I have developed two loads that generate virtually the same PF using two bullets:  170gr LSWC and 180gr LTC, both from LaserCast.  Both loads use Titegroup powder.  Both generate a 168 PF.  The actual loads do not matter here for this discussion.

Today I took both loads up against each other and paid attention to felt recoil.  The 170gr recoil was NOTICABLY sharper than the 180gr.  We are talking half (or less) of the muzzle flip with the 180gr compared to the 170gr.  Both loads were run over the chronograph and the PFs are within 1 of each other.

Now, then this simply upholds the common dogma.  However...

Back in physics they taught us that Force=Mass x Acceleration.  This essentially is an equivalent equation to what we use to derive PF.  Mr. Newton told us that for every action there is an equal and opposite reaction.

So, why does the heavier bullet generate less felt recoil?  Is this a function of the recoil spring?  Or ???

Inquiring minds need to know.  No, not losing sleep over this and yes, I will be switching to the 180gr shortly, once I get an order in from LaserCast.

Cheers!

Kevin

(Edited by kimel at 11:04 pm on Jan. 5, 2003)

(Edited by kimel at 11:05 pm on Jan. 5, 2003)

[gm iprod]

PF favours heavy bullets. Muzzle energy (ft/lbs) favours velocity.

Ft/lbs are what actually cause recoil. The lighter / faster projectile would actually produce more ft / lbs energy. Also it will utilize more powder = more gas and more thrust. The thrust will try to arrive at a slightly higher velocity?? As the gun recoils it rotates around the joint of your wrist. Because you have less time to react to this rotational force the muzzle will rise. But with more time to control the rotation with the heavier bullet you will be able to physically resist some of the rotation. You will not realize that you do this, but it will happen.

MHO.

[Guy Neill]

Power Factor is momentum.  Loads giving equal Momentum will give equal recoil.  The difference is Impulse, force times time.  The lighter bullets have the force act in a shorter time, giving a sharper "feel" to the recoil.

Guy

[kimel]

Ah ha!  Now I remember why I got a "C" in that semester of Engineering Physics and a better grade in the semester focusing on E/M and Optical theory.  Oh well.

Thanks for the explanations.  

Cheers!

Kevin